Seibal is a major ruin of the southern Maya lowlands, its vast ceremonial center covering several high hills on the banks of the Pasi?n River in the Guatemalan Department of Pet?n. In five volumes published over a 15-year period, the archaeological team headed by Gordon R. Willey presents a comprehensive review of their fieldwork from 1964 to 1968 and the results of many years of subsequent data analysis.